Pharmaceutical compounds

ABSTRACT

Benzimidazole derivatives of formula (I): (Formula (I)) wherein: R 1  is —(CH 2 ) m —R 7 , (Formula (II)) or (Formula (III)); R 2  is H, halo, —(CH 2 ) m —NH 2 , —(CH 2 ) n —C(═NH)—NH 2  or —(CH 2 ) n —NH—(CH 2 ) m —NHR 9 ; R 3  is H, F or Cl; each of R 4 , R 5  and R 6  is independently H or F; R 7  is C 1 -C 6  alkyl, CF 3 , —SO 2 R 11 , —NH—(CH 2 ) 2 —(NH) r —R 8 , —NH—CH(R 8 R 9 ) or a group of the following formula (A): (Formula (A)): W is —(CH 2 ) m , —CH 2 —O—CH 2 —, —CH 2 —S—CH 2 —, —(CH 2 ) r —S(O) 2 —CH 2 — or —(CH 2 ) r —NR 8 —CH 2 —; m is an integer of 1 to 3; n is 1 or 2; p is 1 and V is CH; or p is 0 and V is N; q is 0 or 1; r is 0 or 1; R is H, —SO 2 R 11 , —SO 2 CF 3 , —COR 11 , —C(O)OR 11 , —CON(R 9 ) 2  or —(CH 2 ) n SO 2 R 11 ; R 9  is H or C 1 -C 6  alkyl, each R 9  being the same or different when two are present; R 10  is —SO 2 R 11 , —SO 2 CF 3 , —COR 11 , —CON(R 9 ) 2  or —(CH 2 ) n SO 2 R 11 ; and R 11  is C 1 -C 6  alkyl; and the pharmaceutically acceptable salts thereof are inhibitors of RSV and can therefore be used to treat or prevent an RSV infection.

FIELD OF THE INVENTION

The present invention relates to benzimidazole compounds and to theiruse in treating or preventing a respiratory syncytial virus (RSV)infection.

BACKGROUND TO THE INVENTION

RSV is a negative-sense, single-stranded RNA virus of theParamyxoviridae family. RSV is readily transmitted by secretions from aninfected person via surfaces or hand-to-hand transfer. Unlike influenza,it is not transmitted by small-particle aerosols. Following successfulinoculation, the incubation period is between four and six days duringwhich time the virus spreads from the nasopharynx to the lowerrespiratory tract by fusion of infected with uninfected cells and bysloughing of the necrotic epithelium. In infants, coupled with increasedmucus secretion and oedema, this can lead to mucus plugging causinghyper-inflation and collapse of distal lung tissue indicative ofbronchiolitis. Hypoxia is common and the ability to feed is oftenimpaired because of respiratory distress. In RSV pneumonia, inflammatoryinfiltration of the airways consists of mononuclear cells and is moregeneralised, with involvement of the bronchioles, bronchi and alveoli.The duration and degree of viral shedding has been found to correlatewith the clinical signs and severity of disease.

RSV is the leading cause of serious respiratory tract infections ininfants and young children throughout the world. The highest morbidityand mortality occurs in those born prematurely and for those withchronic lung or heart disease, although many infants hospitalised forRSV infection are otherwise healthy. Severe RSV infection in infancy canlead to several years of recurrent wheezing and is linked to the laterdevelopment of asthma.

RSV is also a major cause of morbidity and mortality in the elderly andin immunocompromised children and adults as well as those with chronicobstructive pulmonary disease (COPD) and congestive heart failure (CHF).

RSV has a seasonal incidence; it is highly predictable and occurs in thewinters of both hemispheres, from September to May in Europe and NorthAmerica, peaking in December and January, and can occur throughout theyear in tropical countries. It affects >90% of infants and youngchildren by the age of two years and as natural immunity is short-lived;many will be re-infected each year. As with influenza, in elderlypeople, RSV causes around 10% of winter hospitalisations with anassociated mortality of 10%.

Current anti-RSV treatment involves the use of a monoclonal antibody toRSV, called palivizumab. Such use of palivizumab is a prophylactic,rather than therapeutic, treatment of RSV. Although this antibody isoften effective, its use is restricted to preterm infants and infants athigh risk. Indeed, its limited utility means that it is unavailable formany people in need of anti-RSV treatment. There is therefore an urgentneed for effective alternatives to existing anti-RSV treatment.

Additionally, several compounds have been proposed as inhibitors of RSV,including benzimidazole-based compounds. For example, K D Combrink etal., Bioorganic & Medicinal Chemistry Letters, 17 (2007), 4784-4790discloses the compound BMS-433771 and variants thereof. Furtherbenzimidazole-based compounds are disclosed in WO-02/062290,WO-03/053344 and WO-10/103306.

WO 2013/068769 and WO2016/055780 disclose benzimidazole compounds havingactivity against RSV. However there exists a need to identify furthercompounds, and in particular compounds having favourable pharmacokineticprofiles.

SUMMARY OF THE INVENTION

It has now been found that a novel series of benzimidazole compounds areactive as RSV inhibitors with favourable pharmacokinetics. Accordingly,the present invention provides a compound which is a benzimidazole offormula (I):

wherein:

R¹ is —(CH₂)_(m)—R⁷,

R² is H, halo, —(CH₂)_(m)—NH₂, —(CH₂)_(n)—C(═NH)—NH₂ or—(CH₂)_(n)—NH—(CH₂)_(m)—NHR⁹;

R³ is H, F or Cl;

each of R⁴, R⁵ and R⁶ is independently H or F;

R⁷ is C₁-C₆ alkyl, CF₃, —SO₂R¹¹, —NH—(CH₂)₂—(NH)_(r)—R⁸, —NH—CH(R⁸R⁹) ora group of the following formula (A):

W is —(CH₂)_(m)—, —CH₂—O—CH₂—, —CH₂—S—CH₂—, —(CH₂)_(r)—S(O)₂—CH₂— or—(CH₂)_(r)—NR⁸—CH₂—;

m is an integer of 1 to 3;

n is 1 or 2;

p is 1 and V is CH; or p is 0 and V is N;

q is 0 or 1;

r is 0 or 1;

R⁸ is H, —SO₂R¹¹, —SO₂CF₃, —COR¹¹, —C(O)OR¹¹, —CON(R⁹)₂ or—(CH₂)_(n)SO₂R¹¹;

R⁹ is H or C₁-C₆ alkyl, each R⁹ being the same or different when two arepresent;

R¹⁰ is —SO₂R¹¹, —SO₂CF₃, —COR¹¹, —CON(R⁹)₂ or —(CH₂)_(n)SO₂R¹¹; and

R¹¹ is C₁-C₆ alkyl;

or a pharmaceutically acceptable salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

When any group, ring, substituent or moiety defined herein issubstituted, it is typically substituted by Q as defined below.

A C₁₋₆ alkyl group or moiety is linear or branched. A C₁₋₆ alkyl groupis typically a C₁₋₄ alkyl group, or a C₄₋₆ alkyl group. Examples of C₁₋₆alkyl groups and moieties include methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl (i.e. 3-methylbut-1-yl),t-pentyl (i.e. 2-methylbut-2-yl), neopentyl (i.e.2,2-dimethylpropan-1-yl), n-hexyl, i-hexyl (i.e. 4-methylpentan-1-yl),t-hexyl (i.e. 3-methylpentan-3-yl) and neopentyl (i.e.3,3-dimethylbutan-1-yl). For the avoidance of doubt, where two alkylmoieties are present in a group, the alkyl moieties may be the same ordifferent. A C₁₋₆ alkyl group is unsubstituted or substituted, typicallyby one or more groups Q as defined below. For example, a C₁₋₆ alkylgroup is unsubstituted or substituted by 1, 2 or 3 groups Q as definedbelow.

Q is halo, nitro, —CN, OH, C₁₋₆ alkoxy, C₁₋₆ hydroxyalkyl, C₁₋₆alkylthio, C₁₋₆ haloalkyl, C₁₋₄ haloalkoxy, —CO₂R′″, —NR′″₂, —SR′″,—S(═O)R′″, —S(═O)₂R′″, C₃-C₁₀ cycloalkyl, 5 to 10-membered heterocyclyl,5- to 12-membered aryl or 5- to 12-membered heteroaryl, wherein each R′″is independently selected from H, C₁₋₆ alkyl, C₃₋₁₀ cycloalkyl, 5 to10-membered heterocyclyl, 5- to 12-membered aryl and 5- to 12-memberedheteroaryl.

A C₁₋₆ alkoxy group is linear or branched. It is typically a C₁₋₄ alkoxygroup, for example a methoxy, ethoxy, propoxy, i-propoxy, n-propoxy,n-butoxy, sec-butoxy or tert-butoxy group. A C₁₋₆ alkoxy group isunsubstituted or substituted, typically by one or more groups Q asdefined.

A C₁₋₆ alkylthio group is linear or branched. It is typically a C₁₋₄alkylthio group, for example a methylthio, ethylthio, propylthio,i-propylthio, n-propylthio, n-butylthio, sec-butylthio or tert-butylthiogroup. A C₁₋₆ alkyltho group is unsubstituted or substituted, typicallyby one or more groups Q as defined above.

A halogen or halo group is F, Cl, Br or I. Preferably it is F or Cl. AC₁₋₆ alkyl group substituted by halogen may be denoted “C₁₋₆ haloalkyl”,which means a C₁₋₆ alkyl group as defined above in which one or morehydrogens is replaced by halo. Likewise a C₁₋₆ alkoxy group substitutedby halogen may be denoted “C₁₋₆ haloalkoxy”, which means a C₁₋₆ alkoxygroup as defined above in which one or more hydrogens is replaced byhalo.

Typically, C₁₋₆ haloalkyl or C₁₋₆ haloalkoxy is substituted by 1, 2 or 3said halogen atoms. Haloalkyl and haloalkoxy groups include perhaloalkyland perhaloalkoxy groups such as —CX₃ and —OCX₃ wherein X is a halogen,for example —CF₃—CCl₃—OCF₃ and —OCCl₃.

A C₁₋₆ hydroxyalkyl group is a C₁₋₆ alkyl group as defined above,substituted by one or more OH groups. Typically, it is substituted byone, two or three OH groups. Preferably, it is substituted by a singleOH group.

A 5- to 12-membered aryl group is an aromatic carbocyclic groupcontaining from 5 to 12 carbon atoms, for instance from 6 to 10 carbonatoms, such as 6 or 10 carbon atoms. It is monocyclic or a fusedbicyclic ring system in which an aromatic ring is fused to anotheraromatic carbocyclic ring. Examples of a 5- to 12-membered aryl groupinclude phenyl and naphthyl. When substituted, an aryl group istypically substituted by C₁₋₄ alkyl or a group Q as defined above, forinstance by 1, 2 or 3, groups selected from a C₁₋₄ alkyl group and agroup Q as defined above.

A C₃₋₁₀ cycloalkyl group is a saturated hydrocarbon ring having from 3to 10 carbon atoms. A C₃₋₁₀ cycloalkyl group may be, for instance, C₃-C₇cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, orcycloheptyl. Typically it is C₃-C₆ cycloalkyl, or C₄-C₆ cycloalkyl, forexample cyclobutyl, cyclopentyl or cyclohexyl. In one embodiment it iscyclobutyl. A C₃₋₁₀ cycloalkyl group is unsubstituted or substituted,typically by one or more groups Q as defined above.

A 5- to 12-membered heteroaryl group or moiety is a 5- to 12-memberedaromatic heterocyclic group which contains 1, 2, 3, or 4 heteroatomsselected from O, N and S. It is monocyclic or bicyclic. Typically itcontains one N atom and 0, 1, 2 or 3 additional heteroatoms selectedfrom O, S and N. It may be, for example, a 5- to 7-membered heteroarylgroup, for instance a 5- or 6-membered N-containing heteroaryl group.

Examples include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl,thienyl, pyrazolidinyl, pyrrolyl, oxadiazolyl, oxazolyl, isoxazolyl,thiazolyl, thiadiazolyl, imidazolyl and pyrazolyl groups. Furanyl,thienyl, pyridyl and pyrimidyl groups are preferred. When substituted, aheteroaryl group is typically substituted by one or more, e.g. 1, 2 or3, groups selected from C₁₋₄ alkyl and a group Q as defined above.

A 5- to 10-membered heterocyclyl moiety is a monocyclic or bicyclicnon-aromatic, saturated or unsaturated C₅₋₁₀ carbocyclic ring, in whichat least one, for example 1, 2 or 3, carbon atoms in the ring arereplaced with an atom or group selected from O, S, SO, SO₂, CO and N.Typically, it is a saturated C₅₋₁₀ ring in which 1, 2 or 3 of the carbonatoms in the ring are replaced with an atom or group selected from O, S,SO₂, CO and NH. More typically it is a monocyclic ring, preferably amonocyclic C₅-C₆ ring. Examples include piperidyl, piperidin-2,6-dionyl,piperidin-2-onyl, piperazinyl, morpholinyl, thiomorpholinyl,S,S-dioxothiomorpholinyl, 1,3-dioxolanyl, pyrrolidinyl, imidazol-2-onyl,pyrrolidin-2-onyl, tetrahydrofuranyl and tetrahydropyranyl moieties.

For the avoidance of doubt, although the above definitions of heteroaryland heterocyclyl groups refer to an “N” atom which can be present in thering, as will be evident to a skilled chemist the N atom will beprotonated (or will carry a substituent as defined above) if it isattached to each of the adjacent ring atoms via a single bond. Suchprotonated forms are embraced within the present definitions ofheteroaryl and heterocyclyl groups.

In one embodiment of the benzimidazoles of formula (I), R¹ is—(CH₂)_(m)—R⁷ in which m is 2 or 3 and R⁷ is —NH—(CH₂)₂—(NH)_(r)—R⁸wherein r is 0 or 1 and R⁸ is selected from —SO₂Me, —SO₂Et and —SO₂CF₃.

In another embodiment of the benzimidazoles of formula (I), R¹ is—(CH₂)_(m)—R⁷ in which m is 2 or 3 and R⁷ is C₁-C₆ alkyl, CF₃ or—SO₂R¹¹. In this embodiment —SO₂R¹¹ is typically —SO₂Me or —SO₂Et.

In a further embodiment R¹ is —(CH₂)_(m)—R⁷ in which m is 2 or 3 and R⁷is —NH—CH(R⁸R⁹) wherein R⁸ is —CON(RH₂ or —CONMe₂ and R⁹ is C₁-C₆ alkyl.

In another embodiment R¹ is —(CH₂)_(m)—R⁷ in which m is 2 or 3 and R⁷ isis a group of formula (A) in which p is 1, q is 0, V is CH and W is—(CH₂)—S(O)₂—CH₂— or —(CH₂)—NR⁸—CH₂— in which r is 0 and R⁸ is —SO₂Me or—SO₂Et.

In a yet further embodiment R¹ is —(CH₂)_(m)—R⁷ in which m is 2 or 3 andR⁷ is a group of formula (A) in which p is 0, V is N, W is —(CH₂)_(m)—in which m is an integer of 1 to 3, q is 1 and R¹⁰ is —SO₂Me, —SO₂Et,—CONH₂ or —CONMe₂.

In another embodiment R¹ is —(CH₂)_(m)—R⁷ in which m is 2 or 3 and R⁷ isa group of formula (A) in which p is 0, V is N, q is 0 and W is—CH₂O—CH₂—, —CH₂—S—CH₂—, —(CH₂)_(r)—S(O)₂—CH₂— or —(CH₂)_(r)—NR⁸—CH₂— inwhich r is 0 or 1 and R⁸ is —SO₂Me, —SO₂Et or —COMe.

Alternatively, R¹ is

or in which R⁸ is H, —SO₂R¹¹, —COMe, —C(O)OR¹¹, —CON(R⁹)₂ or —(CH₂)_(n)SO₂R¹¹. In this embodiment —SO₂R¹¹ is typically —SO₂Me or —SO₂Et.—CON(R⁹)₂ is typically —CONH₂ or —CONMe₂. —(CH₂)_(n)SO₂R¹¹ is typically—CH₂CH₂SO₂Me.

When in formula (I) R⁷ is a group of formula (A) and q is 1, the ringsubstituent R¹⁰ may be bonded to any available ring carbon atom.

When W in formula (A) is —(CH₂)_(r)—NR⁸—CH₂—, q is typically 0.

Examples of the group of formula (A) include the following structures:

Group R² in formula (I) is typically H, F, Cl or —CH₂NH₂. More typicallyit is Cl or —CH₂NH₂.

The group R⁸ may be, for instance, H, —SO₂Me, —SO₂Et, —SO₂CF₃, —COMe,—CONMe₂, —CONH₂ or —CH₂CH₂SO₂Me.

The group R¹⁰ may be, for instance, —SO₂Me, —SO₂Et, —SO₂CF₃, —COMe,—CONMe₂, —CONH₂ or —CH₂CH₂SO₂Me.

In one embodiment of formula (I), the substituents are as follows:

-   -   R¹ is —(CH₂)_(m)—R⁷,

-   -   R² is H, halo, —(CH₂)_(m)—NH₂, —(CH₂)_(n)—C(═NH)—NH₂ or        —(CH₂)_(n)—NH—(CH₂)_(m)—NHR⁹;    -   R³ is H, F or Cl;    -   each of R⁴, R⁵ and R⁶ is independently H or F;    -   R⁷ is C₁-C₆ alkyl, CF₃, —NH—(CH₂)₂—(NH)_(r)—R⁸, —NH—(CHR⁸R⁹) or        a group of the following formula (A):

-   -   W is —(CH₂)_(m)—, —CH₂—O—CH₂—, —CH₂—S—CH₂—,        —(CH₂)_(r)—S(O)₂—CH₂— or —(CH₂)_(r)—NR⁸—CH₂—;    -   m is an integer of 1 to 3;    -   n is 1 or 2;    -   p is 1 and V is CH; or p is 0 and V is N;    -   q is 0 or 1;    -   r is 0 or 1;    -   R⁸ is H, —SO₂Me, —SO₂Et, —SO₂CF₃, —COMe, —CONMe₂, —CONH₂ or        —CH₂CH₂SO₂Me;    -   R⁹ is H or C₁-C₆ alkyl; and    -   R¹⁰ is —SO₂Me, —SO₂Et, —SO₂CF₃, —COMe, —CONMe₂, —CONH₂ or        —CH₂CH₂SO₂Me.

Specific compounds of the invention include the following:

-   1-{[5-Chloro-1-(4,4,4-trifluorobutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-({5-Chloro-1-[3-(4-methanesulfonylpiperazin-1-yl)propyl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-[(5-Chloro-1-{3-[(2-methanesulfonylethyl)amino]propyl}-1H-1,3-benzodiazol-2-yl)methyl]-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-({5-Chloro-1-[3-(3-methanesulfonylpyrrolidin-1-yl)propyl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-Chloro-1-(3-methanesulfonylpropyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   tert-Butyl    4-{5-chloro-2-[(3,3-difluoro-2-oxo-2,3-dihydro-1H-indol-1-yl)methyl]-1H-1,3-benzodiazol-1-yl}piperidine-1-carboxylate;-   1-{[5-Chloro-1-(piperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-Chloro-1-(1-methanesulfonylpiperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-({5-Chloro-1-[1-(ethanesulfonyl)piperidin-4-yl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,6-trifluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,7-trifluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,4-trifluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-4-chloro-3,3-difluoro-2,3-dihydro-1H-indol-2-one;-   1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,5-trifluoro-2,3-dihydro-1H-indol-2-one;-   and the pharmaceutically acceptable salts thereof.

The compounds of the invention may contain asymmetric or chiral centres,and therefore exist in different stereoisomeric forms. It is intendedthat all stereoisomeric forms of the compounds of the invention,including but not limited to, diastereomers, enantiomers andatropisomers, as well as mixtures thereof such as racemic mixtures, formpart of the present invention. Compounds of Formula (I) containing oneor more chiral centre may be used in enantiomerically ordiastereoisomerically pure form, or in the form of a mixture of isomers.

The present invention embraces all geometric and positional isomers ofcompounds of the invention as defined above. For example, if a compoundof the invention incorporates a double bond or a fused ring, the cis-and trans-forms, as well as mixtures thereof, are embraced within thescope of the invention. Both the single positional isomers and mixtureof positional isomers are also within the scope of the presentinvention.

The compounds of the present invention may exist in unsolvated as wellas solvated forms with pharmaceutically acceptable solvents such aswater, ethanol, and the like, and it is intended that the inventionembrace both solvated and unsolvated forms.

The compounds of the present invention may exist in different tautomericforms, and all such forms are embraced within the scope of theinvention. The term “tautomer” or “tautomeric form” refers to structuralisomers of different energies which are interconvertible via a lowenergy barrier. For example, proton tautomers (also known as prototropictautomers) include interconversions via migration of a proton, such asketo-enol tautomerizations. Valence tautomers include interconversionsby reorganization of some of the bonding electrons.

Compounds of the invention can be prepared by synthetic methodsdescribed in the Examples that follow, or by analogy with such methods.

A benzimidazole of formula (I) can be converted into a pharmaceuticallyacceptable salt thereof, and a salt can be converted into the freecompound, by conventional methods. For instance, a benzimidazole offormula (I) can be contacted with a pharmaceutically acceptable acid toform a pharmaceutically acceptable salt. A pharmaceutically acceptablesalt is a salt with a pharmaceutically acceptable acid or base.

Pharmaceutically acceptable acids include both inorganic acids such ashydrochloric, sulphuric, phosphoric, diphosphoric, hydrobromic or nitricacid and organic acids such as citric, fumaric, maleic, malic, ascorbic,succinic, tartaric, benzoic, acetic, methanesulphonic, ethanesulphonic,benzenesulphonic or p-toluenesulphonic acid. Pharmaceutically acceptablebases include alkali metal (e.g. sodium or potassium) and alkali earthmetal (e.g. calcium or magnesium) hydroxides and organic bases such asalkyl amines, aralkyl amines and heterocyclic amines.

Compounds of the present invention have been found in biological teststo be inhibitors of respiratory syncytial virus (RSV). The compounds aretherefore therapeutically useful. Accordingly, the present inventionfurther provides a compound which is a benzimidazole of formula (I), asdefined above, or a pharmaceutically acceptable salt thereof, for use ina method of treating the human or animal body by therapy. The inventionalso provides a compound of the invention as defined above for use in amethod treating or preventing an RSV infection. Still further, thepresent invention provides the use of a compound of the invention asdefined above in the manufacture of a medicament for use in treating orpreventing an RSV infection. A subject suffering from or susceptible toan RSV infection may thus be treated by a method comprising theadministration thereto of a compound of the invention as defined above.The condition of the subject may thereby be improved or ameliorated.

The RSV infection is typically a respiratory tract infection. The RSVinfection may be an infection in a child, for instance a child under tenyears of age or an infant under two years of age. In one embodiment theinvention provides a compound as defined above for use in treating orpreventing an RSV infection in paediatric patients. Alternatively theinfection may be an infection in a mature or elderly adult, for instancean adult over 60 years of age, an adult over 70 years of age, or anadult over 80 years of age. The invention further provides a compoundfor use in treating or preventing an RSV infection in geriatricpatients.

The RSV infection may be an infection in an immunocompromised individualor an individual suffering from COPD or CHF. In another embodiment, theRSV infection is an infection in a non-compromised individual, forinstance an individual who is otherwise healthy.

A compound of the present invention can be administered in a variety ofdosage forms, for example orally such as in the form of tablets,capsules, sugar- or film-coated tablets, liquid solutions or suspensionsor parenterally, for example intramuscularly, intravenously orsubcutaneously. The compound may therefore be given by injection,infusion, or by inhalation or nebulaisation. The compound is preferablygiven by oral administration.

The dosage depends on a variety of factors including the age, weight andcondition of the patient and the route of administration. Daily dosagescan vary within wide limits and will be adjusted to the individualrequirements in each particular. Typically, however, the dosage adoptedfor each route of administration when a compound is administered aloneto adult humans is 0.0001 to 650 mg/kg, most commonly in the range of0.001 to 10 mg/kg, body weight, for instance 0.01 to 1 mg/kg. Such adosage may be given, for example, from 1 to 5 times daily. Forintravenous injection a suitable daily dose is from 0.0001 to 1 mg/kgbody weight, preferably from 0.0001 to 0.1 mg/kg body weight. A dailydosage can be administered as a single dosage or according to a divideddose schedule.

A unit dose form such as a tablet or a capsule will usually contain1-250 mg of active ingredient. For example, a compound of formula (I)could be administered to a human patient at a dose of between 100-250 mgeither once a day, twice or three times a day. For example, a compoundof formula (I) could be administered to a human patient at a dose ofbetween 100-250 mg either once a day, twice or three times a day.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be used on their own. Alternatively, they may beadministered in the form of a pharmaceutical composition. The presentinvention therefore also provides a pharmaceutical compositioncomprising a compound of formula (I) or a pharmaceutically acceptablesalt thereof as hereinbefore defined, in association with apharmaceutically acceptable adjuvant, diluent or carrier. Conventionalprocedures for the selection and preparation of suitable pharmaceuticalformulations are described in, for example, “Pharmaceuticals—The Scienceof Dosage Form Designs”, M. E. Aulton, Churchill Livingstone, 1988.

Depending on the mode of administration, the pharmaceutical compositionwill preferably comprise from 0.05 to 99% w (percent by weight), morepreferably from 0.05 to 80% w, still more preferably from 0.10 to 70% w,and even more preferably from 0.10 to 50% w, of active ingredient, allpercentages by weight being based on total composition.

The invention further provides a process for the preparation of apharmaceutical composition of the invention which comprises mixing acompound of formula (I) or a pharmaceutically acceptable salt thereof ashereinbefore defined with a pharmaceutically acceptable adjuvant,diluent or carrier.

The compounds of the invention may be administered in a variety ofdosage forms. Thus, they can be administered orally, for example astablets, troches, lozenges, aqueous or oily suspensions, solutions,dispersible powders or granules. The compounds of the invention may alsobe administered parenterally, whether subcutaneously, intravenously,intramuscularly, intrasternally, transdermally, by infusion techniquesor by inhalation or nebulisation. The compounds may also be administeredas suppositories.

Solid oral forms of the pharmaceutical composition of the invention maycontain, together with the active compound, diluents, e.g. lactose,dextrose, saccharose, cellulose, corn starch or potato starch;lubricants, e.g. silica, talc, stearic acid, magnesium or calciumstearate, and/or polyethylene glycols; binding agents; e.g. starches,arabic gums, gelatin, methylcellulose, carboxymethylcellulose orpolyvinyl pyrrolidone; disaggregating agents, e.g. starch, alginic acid,alginates or sodium starch glycolate; effervescing mixtures; dyestuffs;sweeteners; wetting agents, such as lecithin, polysorbates,laurylsulfates; and, in general, non toxic and pharmacologicallyinactive substances used in pharmaceutical formulations. Suchpharmaceutical preparations may be manufactured in known manner, forexample, by means of mixing, granulating, tableting, sugar coating, orfilm coating processes.

Liquid dispersions for oral administration may be syrups, emulsions andsuspensions. The syrups may contain as carriers, for example, saccharoseor saccharose with glycerine and/or mannitol and/or sorbitol.

Suspensions and emulsions may contain as carrier, for example a naturalgum, agar, sodium alginate, pectin, methylcellulose,carboxymethylcellulose, or polyvinyl alcohol. The suspension orsolutions for intramuscular injections may contain, together with theactive compound, a pharmaceutically acceptable carrier, e.g. sterilewater, olive oil, ethyl oleate, glycols, e.g. propylene glycol, and ifdesired, a suitable amount of lidocaine hydrochloride. Further suitablecarriers for suspensions include sterile water, hydroxypropylmethylcellulose (HPMC), polysorbate 80, polyvinylpyrrolidone (PVP), aerosolAOT (i.e. sodium 1,2-bis(2-ethylhexoxycarbonyl)ethanesulphonate),pluronic F127 and/or captisol (i.e. sulfobutylether-beta-cyclodextrin).

The compounds of the invention may, for example, be formulated asaqueous suspensions in a carrier selected from:

(i) 0.5% w/v hydroxypropylmethyl cellulose (HPMC)/0.1% w/v polysorbate80;

(ii) 0.67% w/v polyvinylpyrrolidone (PVP)/0.33% w/v aerosol AOT (sodium1,2-bis(2-ethylhexoxycarbonyl)ethanesulphonate);

(iii) 1% w/v pluronic F 127; and

(iv) 0.5% w/v polysorbate 80.

The carriers may be prepared by standard procedures known to those ofskill in the art. For example, each of the carriers (i) to (iv) may beprepared by weighing the required amount of excipient into a suitablevessel, adding approximately 80% of the final volume of water andmagnetically stirring until a solution is formed. The carrier is thenmade up to volume with water. The aqueous suspensions of compounds offormula I may be prepared by weighing the required amount of a compoundof formula I into a suitable vessel, adding 100% of the required volumeof carrier and magnetically stirring.

Solutions for injection or infusion may contain as carrier, for example,sterile water or preferably they may be in the form of sterile, aqueous,isotonic saline solutions.

The compounds of the invention may also be administered in conjunctionwith other compounds used for the treatment of viral infections. Thus,the invention further relates to combination therapies wherein acompound of the invention, or a pharmaceutically acceptable saltthereof, or a pharmaceutical composition or formulation comprising acompound of the invention, is administered concurrently or sequentiallyor as a combined preparation with another therapeutic agent or agents,for the treatment or prevention of a viral infection, particularlyinfection by RSV.

Herein, where the term “combination” is used it is to be understood thatthis refers to simultaneous, separate or sequential administration. Inone aspect of the invention “combination” refers to simultaneousadministration. In another aspect of the invention “combination” refersto separate administration. In a further aspect of the invention“combination” refers to sequential administration. Where theadministration is sequential or separate, the delay in administering thesecond component should not be such as to lose the beneficial effect ofthe combination.

Suitable therapeutic agents for use in the combination therapies include

(i) RSV nucleocapsid (N)-protein inhibitors;

(ii) other RSV protein inhibitors, such as those that inhibit thephosphoprotein (P) protein and large (L) protein;

(iii) anti-RSV monoclonal antibodies, such as the F-protein antibodies;

(iv) immunomodulating toll-like receptor compounds;

(v) other respiratory virus anti-virals, such as anti-influenza andanti-rhinovirus compounds; and/or

(vi) anti-inflammatory compounds.

The RSV nucleocapsid (N)-protein plays a pivotal role in viraltranscription and replication, mediating the interaction between thegenomic RNA and the virally encoded RNA-dependent RNA polymerase. TheRSV P- and L-proteins are components of RSV's virally encodedRNA-dependent RNA polymerase.

According to a further aspect of the invention, there is provided acompound of the formula (I) or a pharmaceutically acceptable saltthereof as hereinbefore defined in combination with one or more of thetherapeutic agents listed as (i) to (vi) above for use in the treatmentof RSV.

The following Examples illustrate the invention. They do not however,limit the invention in any way.

EXAMPLES

Reagents were obtained from commercial sources and were used withoutfurther purification. All temperatures are in ° C. TLC was performed onaluminium backed silica gel plates with fluorescence indicator at 254 nM(median pore size 60 Å). Flash column chromatography was performed usinga Biotage Isolera One system using KP-Sil, Ultra or KP-NH columns. NMRspectra were recorded on a 400 MHz spectrometer at ambient probetemperature (nominal 295K). Chemical shifts (6) are given in ppm andcalibrated by using the residual peak of the solvent as the internalstandard (CDCl₃, δ_(H)=7.26 ppm, δ_(C)=77.16 ppm; DMSO-d₆, =2.50 ppm,δ_(C)=39.52 ppm). Coupling constants are given in Hertz (Hz). LRMS wererecorded using an Advion Plate Express expression^(L) compact massspectrometer equipped with either an APCI or ESI ion source.

Abbreviations

DMSO Dimethyl sulfoxide EtOAc Ethyl acetate EtOH Ethanol h Hour(s) iPrOHIsopropanol LRMS Low resolution mass spectrometry MeCN Acetonitrile MeOHMethanol rt room temperature TFA Trifluoroacetic acid

PREPARATORY EXAMPLES 1A: 3,3-Difluoro-2,3-dihydro-1H-indol-2-one

Prepared by adaptation of the deoxyfluorination procedure reported bySingh et al, J Org. Chem. 2001 Sep. 1; 66(19):6263-7. Isatin (3.05 g,20.72 mmol) was dissolved in anhydrous CH₂Cl₂ (50 mL) under an inertatmosphere and cooled to 0° C. Diethylaminosulfur trifluoride (8.29 mL,62.74 mmol) was added, and the reaction stirred for 23 h at rt. Aftercooling to 0° C., the reaction was cautiously quenched with saturatedaqueous NaHCO₃ solution until no further effervescence was observed, andextracted with CH₂Cl₂ (3×50 mL). The combined organic extracts werewashed successively with saturated aqueous NaHCO₃ solution, water andbrine (50 mL each), dried (MgSO₄) and the solvent removed under reducedpressure. Purification by flash chromatography (SiO₂; EtOAc/heptane;10-32%) afforded a yellow solid, which was triturated with heptane toafford the product as an off-white solid (2.637 g, 75%). ¹H NMR (400MHz, CDCl₃): δ 7.95 (br s, 1H), 7.57-7.53 (m, 1H), 7.48-7.42 (m, 1H),7.17 (t, J=7.7 Hz, 1H), 6.96-6.92 (m, 1H). LRMS (APCI-) m/z 167.9 [M−H]⁻

The following intermediate compounds were prepared by the same generaldeoxyfluorination procedure.

TABLE 1 Examples prepared via general deoxyfluorination procedure

Preparatory ¹H NMR δ LRMS Example Name R¹ (400 MHz, CDCl₃) AP-CI− 1B3,3,4-Trifluoro-2,3- 4-F 7.95 (br s, 1H), 7.48-7.41 (m, 1H), 185.9dihydro-1H-indol-2-one 6.87-6.82 (m, 1H), 6.76-6.72 (m, 1H) [M − H]⁻ 1C4-Chloro-3,3-difluoro-2,3- 4-Cl 8.06 (br s, 1H), 7.41-7.35 (m, 1H),201.9 dihydro-1H-indol-2-one 7.11 (d, J = 8.3 Hz, 1H), 6.86-6.82 [M −H]⁻ (m, 1H) 1D 3,3,5-Trifluoro-2,3- 5-F 8.05 (br s, 1H), 7.32-7.27 (m,1H), 185.9 dihydro-1H-indol-2-one 7.21-7.14 (m, 1H), 6.94-6.88 (m, 1H)[M − H]⁻ 1E 3,3,6-Trifluoro-2,3- 6-F 8.19 (br s, 1H), 7.57-7.51 (m, 1H),185.8 dihydro-1H-indol-2-one 6.88-6.82 (m, 1H), 6.72-6.68 (m, 1H) [M −H]⁻ 1F 3,3,7-Trifluoro-2,3- 7-F 7.91 (br s, 1H), 7.39-7.35 (m, 1H),185.9 dihydro-1H-indol-2-one 7.28-7.22 (m, 1H), 7.19-7.12 (m, 1H) [M −H]⁻

2A: 4-Chloro-N-(3,3-diethoxypropyl)-2-nitroaniline

N,N-Diisopropylethylamine (3.397 mL, 19.5 mmol) followed by3,3-diethoxypropan-1-amine (3.154 mL, 19.5 mmol) were added to asolution of 4-chloro-1-fluoro-2-nitrobenzene (1.765 mL, 15 mmol), iniPrOH (35 mL) and heated at 80° C. for 4.5 h. After cooling to rt, thereaction mixture was diluted with EtOAc (100 mL), washed successivelywith H₂O (acidified to ˜pH 6 with 0.01 M aqueous HCl, 4×) and brine (1×,100 mL each), dried (MgSO4) and the solvent removed under reducedpressure to afford the crude product as an orange solid (4.308 g, 97%).¹H NMR (400 MHz, CDCl₃): δ 8.29 (br s, 1H), 8.17 (d, J=2.6 Hz, 1H), 7.37(ddd, J=9.2, 2.6, 0.6 Hz, 1H), 6.83 (d, J=9.2 Hz, 1H), 4.65 (t, J=5.0Hz, 1H), 3.76-3.65 (m, 2H), 3.59-3.49 (m, 2H), 3.44-3.37 (m, 2H),2.07-2.01 (m, 2H), 1.24 (t, J=7.0 Hz, 6H). LRMS (ESI+) m/z 324.9 [M+Na]⁺

2B: tert-Butyl 4-[(4-chloro-2-nitrophenyl)amino]piperidine-1-carboxylate

Prepared by an analogous procedure to intermediate 2A. ¹H NMR (400 MHz,CDCl₃): δ 8.19 (d, J=2.6 Hz, 1H), 8.06 (d, J=7.4 Hz, 1H), 7.40-7.35 (m,1H), 6.84 (d, J=9.3 Hz, 1H), 4.09-3.95 (m, 2H), 3.69-3.60 (m, 1H),3.09-2.98 (m, 2H), 2.09-2.00 (m, 2H), 1.57-1.50 (m, 2H), 1.47 (s, 9H).LRMS (APCI-) m/z 353.9 [M−H]⁻

3A: 4-Chloro-N¹-(3,3-diethoxypropyl)benzene-1,2-diamine

In a 250 mL round-bottom pressure flask4-chloro-N-(3,3-diethoxypropyl)-2-nitroaniline (intermediate 2A) (4.050g, 13.38 mmol) was dissolved in EtOH (100 mL) and platinum on carbon (5wt. % loading, 393 mg) added. The reaction vessel was filled withhydrogen to a pressure of 50 psi and stirred for 3 h. The reactionmixture was filtered through a glass micro fiber filter, washing withEtOH and the solvent removed under reduced pressure. Purification byflash chromatography [SiO₂;CH₂Cl₂/(CH₂Cl₂:EtOH:NH₄OH 80:20:1); 0-25%]afforded the title compound as a dark brown oil (3.440 g, 94%). ¹H NMR(400 MHz, CDCl₃): δ 6.74 (dd, J=8.4, 2.4 Hz, 1H), 6.67 (d, J=2.4 Hz,1H), 6.53 (d, J=8.4 Hz, 1H), 4.65 (t, J=5.4 Hz, 1H), 3.83-3.64 (m, 3H),3.57-3.47 (m, 2H), 3.40 (br s, 2H), 3.17 (t, J=6.4 Hz, 2H), 2.02-1.96(m, 2H), 1.23 (t, J=7.0 Hz, 6H). LRMS (ESI+) m/z 273.1 [M+Na]⁺

3B tert-Butyl 4-[(2-amino-4-chlorophenyl)amino]piperidine-1-carboxylate

Prepared by an analogous procedure to intermediate 3A from intermediate2B. ¹H NMR (400 MHz, CDCl₃): δ 6.75-6.69 (m, 2H), 6.57 (d, J=8.3 Hz,1H), 4.03 (br s, 2H), 3.54-3.26 (m, 3H), 3.00-2.86 (m, 2H), 2.04-1.96(m, 2H), 1.42 (s, 9H), 1.42-1.30 (m, 2H). LRMS (ESI+) m/z 326.3 [M+H]⁺

4A: 5-Chloro-2-(chloromethyl)-1-(3,3-diethoxypropyl)-1H-1,3-benzodiazole

A solution of intermediate 2A (2.524 g, 9.27 mmol) and2-chloro-1,1,1-triethoxyethane (2.499 mL, 18.54 mmol) in EtOH (90 mL)was heated at 75° C. for 7.5 h, then stirred at rt for 12 h. Thevolatiles were removed under reduced pressure and the reaction mixturepurified by flash chromatography (SiO₂; EtOAc/petroleum ether 60/80;0-60%) to give the product as a brown solid (1.537 g, 50%). ¹H NMR (400MHz, CDCl₃): δ 7.74-7.72 (m, 1H), 7.34-7.26 (m, 2H), 4.87 (s, 2H), 4.48(t, J=5.0 Hz, 1H), 4.37 (t, J=7.1 Hz, 2H), 3.68-3.58 (m, 2H), 3.49-3.39(m, 2H), 2.21-2.14 (m, 2H), 1.20 (t, J=7.1 Hz, 6H). LRMS (APCI+) m/z331.1 [M+H]⁺

4B: tert-Butyl4-[5-chloro-2-(chloromethyl)-1H-1,3-benzodiazol-1-yl]piperidine-1-carboxylate

Prepared by an analogous procedure to intermediate 4A from intermediate3B. ¹H NMR (400 MHz, CDCl₃): δ 7.73 (d, J=1.9 Hz, 1H), 7.42 (d, J=8.7Hz, 1H), 7.24 (dd, J=8.8, 2.0 Hz, 1H), 4.85 (s, 2H), 4.52-4.27 (m, 3H),2.98-2.81 (m, 2H), 2.46-2.31 (m, 2H), 2.03-1.93 (m, 2H), 1.52 (s, 9H).LRMS (APCI+) m/z 383.9 [M+H]⁺

5A:1-{[5-Chloro-1-(3,3-diethoxypropyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

A solution of intermediate 4A (293 mg, 0.885 mmol),3,3-di-fluoro-2,3-dihydro-1H-indol-2-one (intermediate 1A, 150 mg, 0.885mmol) and K₂CO₃ (300 mg, 2.167 mmol) in anhydrous MeCN (6 mL) was heatedunder an inert atmosphere at 70° C. for 1 h 45 min. After cooling to rt,the reaction was diluted with EtOAc (30 mL) and washed with H₂O (10 mL).The aqueous layers were extracted with EtOAc (2×20 mL), the combinedorganic extracts washed successively with H₂O and brine (10 mL each),dried (MgSO₄) and the solvent removed under reduced pressure.Purification by flash chromatography (SiO₂, SiO₂, 12-65% EtOAc inheptane) afforded the product as a white solid (303 mg, 74%). ¹H NMR(400 MHz, CDCl₃): δ 7.74 (dd, J=1.9, 0.6 Hz, 1H), 7.56-7.51 (m, 2H),7.49-7.43 (m, 1H), 7.33-7.29 (m, 1H), 7.29-7.24 (m, 1H), 7.17 (t, J=7.7,1H), 5.23 (s, 2H), 4.48 (t, J=5.3 Hz, 1H), 4.35 (t, J=7.0 Hz, 2H),3.66-3.55 (m, 2H), 3.48-3.39 (m, J, 2H), 2.04-1.97 (m, 2H), 1.17 (t,J=7.1 Hz, 6H). LRMS (APCI+) m/z 463.9 [M+H]⁺

The following 5-aminomethylene intermediate compounds were prepared bythe same general procedure described for intermediate 5A from tert-butylN-{[2-(chloromethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-5-yl]methyl}carbamate,denoted intermediate 4C (see Table 2 below).

TABLE 2 5-Aminomethylene intermediates prepared by general procedure

Preparatory ¹H NMR δ Example Name R (400 MHz, CDCl₃) LRMS AP-CI+ 5Btert-butyl N-({2-[(3,3- H 7.67 (br s, 1H), 7.57-7.49 (m, 498.8 [M + H]⁺difluoro-2-oxo-2,3-dihydro- 2H), 7.47-7.41 (m, 1H), 7.30-1H-indol-1-yl)methyl]-1-(3- 7.22 (m, 2H), 7.16 (t, J = 7.7methylbutyl)-1H-1,3- Hz, 1H), 5.20 (s, 2H), 4.88 (br s, benzodiazol-5-1H), 4.43 (d, J = 5.9 Hz, 2H), yl}methyl)carbamate 4.28-4.16 (m, 2H),1.79-1.67 (m, 1H), 1.53-1.45 (m, 11H), 0.97 (d, J = 6.6 Hz, 6H) 5Ctert-butyl N-{[1-(3- 4-F 7.66 (s, 1H), 7.47-7.36 (m, 2H), 517.1 [M + H]⁺methylbutyl)-2-[(3,3,4- 7.31-7.25 (m, 2H), 6.84 (dd, J =trifluoro-2-oxo-2,3-dihydro- 8.9, 7.9 Hz, 1H), 5.19 (s, 2H),1H-indol-1-yl)methyl]-1H- 4.88 (br s, 1H), 4.46-4.39 (m,1,3-benzodiazol-5- 2H), 4.24-4.17 (m, 2H), 1.79- yl]methyl}carbamate1.72 (m, 1H), 1.55-1.44 (m, 11H), 1.01-0.95 (m, 6H) 5D tert-butylN-({2-[(4-chloro- 4-Cl 7.66 (s, 1H), 7.49 (d, J = 8.0 Hz, 533.1 [M + H]⁺3,3-difluoro-2-oxo-2,3- 1H), 7.39-7.34 (m, 1H), 7.30-dihydro-1H-indol-1- 7.23 (m, 2H), 7.09 (d, J = 8.2yl)methyl]-1-(3-methylbutyl)- Hz, 1H), 5.19 (s, 2H), 4.88 (br s,1H-1,3-benzodiazol-5- 1H), 4.46-4.38 (m, 2H), 4.25- yl}methyl)carbamate4.17 (m, 2H), 1.79-1.68 (m, 1H), 1.55-1.44 (m, 11H), 1.01- 0.96 (m, 6H)5E tert-butyl N-{[1-(3- 5-F 7.66 (s, 1H), 7.57 (dd, J = 8.7, 517.2 [M +H]⁺ methylbutyl)-2-[(3,3,5- 3.8 Hz, 1H), 7.36-7.23 (m, 3H),trifluoro-2-oxo-2,3-dihydro- 7.18-7.12 (m, 1H), 5.19 (s, 2H),1H-indol-1-yl)methyl]-1H- 4.88 (br s, 1H), 4.47-4.38 (m,1,3-benzodiazol-5- 2H), 4.24-4.17 (m, 2H), 1.79- yl]methyl}carbamate1.67 (m, 1H), 1.54-1.44 (m, 11H), 1.01-0.95 (m, 6H).

6A:3-{5-Chloro-2-[(3,3-difluoro-2-oxo-2,3-dihydro-1H-indol-1-yl)methyl]-1H-1,3-benzodiazol-1-yl}propanal

HCl (2 M aqueous solution, 3 mL) was added to a solution of intermediate5A (288 mg, 0.621 mmol) in tetrahydrofuran (5 m) and stirred at rt for 7h. The reaction was quenched with saturated aqueous NaHCO₃ solution (˜10mL) and extracted with EtOAc (3×15 mL). The combined organic extractswere washed with brine (15 mL each), dried (MgSO₄) and the solventremoved under reduced pressure. Purification by flash chromatography(SiO₂, 20-100% EtOAc in heptane) afforded a white solid (216 mg, 89%).¹H NMR (400 MHz, CDCl₃): δ 9.74 (s, 1H), 7.76-7.72 (m, 1H), 7.57-7.45(m, 3H), 7.35-7.25 (m, 2H), 7.19 (t, J=7.6 Hz, 1H), 5.32 (s, 2H), 4.61(t, J=6.5 Hz, 2H), 2.95 (t, J=6.4 Hz, 1H). LRMS (APCI+) m/z 390.1 [M+H]⁺

EXAMPLES 1:1-{[5-Chloro-1-(4,4,4-trifluorobutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to 5A from 1A and5-chloro-2-(chloromethyl)-1-(4,4,4-trifluorobutyl)-1H-1,3-benzodiazole.¹H NMR (400 MHz, CDCl₃): δ 7.78-7.77 (m, 1H), 7.59-7.45 (m, 3H),7.33-7.23 (m, 2H), 7.19 (t, J=7.6 Hz, 1H), 5.20 (s, 2H), 4.34-4.28 (m,2H), 2.27-2.14 (m, 2H), 1.95-1.85 (m, 2H). LRMS (APCI+) m/z 444.0 [M+H]⁺

2:1-({5-Chloro-1-[3-(4-methanesulfonylpiperazin-1-yl)propyl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one

1-(Methylsulfonyl)piperazine (26 mg, 0.156 mmol) was added to a solutionof intermediate 6A (61 mg, 0.156 mmol) in 1,2-dichloroethane (3 mL) andstirred at rt for 7.5 h. NaBH(OAc)₃ (46 mg, 0.219 mmol) was then addedand the reaction stirred for 18 h at rt. The reaction was quenched withNaOH (1 M aqueous solution, 5 mL), extracted with CH₂Cl₂ (4×10 mL), thecombined organic extracts washed with brine (5 mL), dried (Na₂SO₄) andthe solvent removed under reduced pressure. Purification by flashchromatography (SiO₂, 50-100% EtOAc in heptane, then 0-5% MeOH in CH₂Cl₂with 1% NH₄OH) afforded the product as a white solid (50 mg, 60%). ¹HNMR (400 MHz, DMSO-d₆): δ 7.78-7.74 (m, 1H), 7.68-7.64 (m, 2H),7.61-7.55 (m, 1H), 7.32-7.23 (m, 3H), 5.36 (s, 2H), 4.36 (t, J=6.8 Hz,2H), 3.11-3.04 (m, 4H), 2.86 (s, 3H), 2.44-2.37 (m, 4H), 2.34-2.26 (m,2H), 2.01-1.91 (m, 2H). LRMS (APCI+) m/z 538.2 [M+H]⁺

The following compounds of the invention were prepared with intermediate6A by the general reductive amination procedure described for thecompound of Example 2.

TABLE 3 Examples prepared via reductive amination

¹H NMR δ LRMS Example Name R¹ (400 MHz, DMSO-d₆) AP-CI+ 31-[(5-Chloro-1-{3-[(2- methanesulfonylethyl) amino]propyl}-1H-1,3-benzodiazol-2-yl)methyl]- 3,3-difluoro-2,3-dihydro- 1H-indol-2-one

7.78-7.74 (m, 1H), 7.67-7.61 (m, 2H), 7.60-7.55 (m, 1H), 7.32-7.19 (m,3H), 5.35 (s, 2H), 4.41-4.32 (m, 2H), 3.24 (t, J = 6.7 Hz, 2H), 3.01 (s,3H), 2.91 (t, J = 6.7 Hz, 2H), 2.06 (s, 1H), 1.94-1.85 (m, 2H) 496.1[M + H]⁺ 4 1-({5-Chloro-1-[3-(3- methanesulfonylpyrrolidin-1-yl)propyl]-1H-1,3- benzodiazol-2-yl}methyl)- 3,3-difluoro-2,3-dihydro-1H-indol-2-one

7.78-7.73 (m, 1H), 7.68-7.63 (m, 1H), 7.60-7.54 (m, 1H), 7.29-7.22 (m,3H), 5.40-5.30 (m, 2H), 4.39- 4.33 (m, 2H), 3.84-3.75 (m, 1H), 2.94 (s,3H), 2.89-2.84 (m, 1H), 2.79-2.73 (m, 1H), 2.64-2.58 (m, 1H), 2.38-2.31(m, 2H), 2.15-2.08 (m, 2H), 2.01-1.93 (m, 2H) 523.1 [M + H]⁺

5:1-{[5-Chloro-1-(3-methanesulfonylpropyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to 5A from 1A and5-chloro-2-(chloromethyl)-1-(3-methanesulfonylpropyl)-1H-1,3-benzodiazole.¹H NMR (400 MHz, DMSO-d₆): δ 7.79-7.74 (m, 1H), 7.70 (d, J=8.8 Hz, 1H),7.66 (d, J=2.0 Hz, 1H), 7.61-7.55 (m, 1H), 7.32 (dd, J=8.7, 2.0 Hz, 1H),7.28-7.23 (m, 2H), 5.34 (s, 2H), 4.47 (t, J=7.5 Hz, 2H), 3.29-3.23 (m,2H), 3.02 (s, 3H), 2.27-2.17 (m, 2H). LRMS (APCI+) m/z 453.7 [M+H]⁺

6: tert-Butyl4-{5-chloro-2-[(3,3-difluoro-2-oxo-2,3-dihydro-1H-indol-1-yl)methyl]-1H-1,3-benzodiazol-1-yl}piperidine-1-carboxylate

Prepared by an analogous procedure to 5A from 1A and 4B. ¹H NMR (400MHz, CDCl₃): δ 7.76 (d, J=2.0, 1H), 7.55-7.38 (m, 4H), 7.21 (dd, J=8.8,2.0 Hz, 1H), 7.19-7.15 (m, 1H), 5.24 (s, 2H), 4.70-4.58 (m, 1H),4.40-4.18 (m, 2H), 2.97-2.83 (m, 2H), 2.37-2.21 (m, 2H), 1.70-1.60 (m,2H), 1.50 (s, 9H). LRMS (APCI+) m/z 516.6 [M+H]⁺

7:1-{[5-Chloro-1-(piperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

TFA (2 mL) was added to a cooled solution (0° C.) of compound 6 (549 mg,1.06 mmol) in CH₂Cl₂ (8 mL) and stirred at rt for 2 h. The reaction wascooled to 0° C., quenched with saturated aqueous NaHCO₃ solution andextracted with CH₂Cl₂ (3×20 mL). The combined organic extracts werewashed with brine (25 mL), dried (Na₂SO₄) and the solvent removed underreduced pressure. Purification by flash chromatography [0-100%EtOH:CH₂Cl₂:NH₄OH (50:8:1) in CH₂Cl₂] afforded the product as a whitesolid (427 mg, 96%). ¹H NMR (400 MHz, CDCl₃): 7.76 (d, J=2.0 Hz, 1H),7.73 (d, J=8.8 Hz, 1H), 7.55-7.49 (m, 2H), 7.48-7.43 (m, 1H), 7.26 (dd,J=8.8, 2.1 Hz, 1H), 7.20-7.15 (m 1H), 5.23 (s, 2H), 4.77-4.68 (m, 1H),3.45-3.37 (m, 2H), 3.03-2.94 (m, 2H), 2.71-2.59 (m, 2H), 1.80-1.72 (m,2H). LRMS (APCI+) m/z 416.8 [M+H]⁺

8:1-{[5-Chloro-1-(1-methanesulfonylpiperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

Methanesulfonyl chloride (23.0 μL, 0.297 mmol) was added to a cooled (0°C.) solution of compound 7 (62 mg, 0.149 mmol) and triethylamine (42.5μL, 0.305 mmol) in anhydrous CH₂Cl₂ (2.5 mL) under N₂ and stirred at rtfor 17 h. The reaction was diluted with CH₂Cl₂ (20 mL), washedsuccessively with saturated aqueous NH₄Cl soln, water and brine (10 mLeach), dried (MgSO₄) and the solvent removed under reduced pressure.Purification by flash chromatography (30-100% EtOAc in heptane) affordeda white solid (32 mg, 43%). ¹H NMR (400 MHz, CDCl₃): 7.77 (d, J=2.0,1H), 7.56-7.44 (m, 4H), 7.26 (dd, J=8.7, 2.0 Hz, 1H), 7.19 (t, J=7.6 Hz,1H), 5.24 (s, 2H), 4.74-4.64 (m, 1H), 4.03-3.96 (m, 2H), 2.93-2.83 (m,5H), 2.61-2.48 (m, 2H), 1.82-7.72 (m, 2H). LRMS (APCI+) m/z 494.7 [M+H]⁺

9:1-({5-Chloro-1-[1-(ethanesulfonyl)piperidin-4-yl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to that described for compound 8 fromcompound 7. ¹H NMR (400 MHz, CDCl₃): δ 7.79 (d, J=2.0 Hz, 1H), 7.58-7.46(m, 4H), 7.29-7.26 (m, 1H), 7.23-7.18 (m, 1H), 5.26 (s, 2H), 4.77-4.67(m, 1H), 4.07-4.00 (m, 2H), 3.10-2.98 (m, 4H), 2.61-2.48 (m, 2H),1.81-1.73 (m, 2H), 1.44 (t, J=7.4 Hz, 3H). LRMS (APCI+) m/z 508.8 [M+H]⁺

10:1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to intermediate 5A from intermediate1A and 5-chloro-2-(chloromethyl)-1-(oxan-4-yl)-1H-1,3-benzodiazole. ¹HNMR (400 MHz, CDCl₃): δ 7.77 (d, J=2.0 Hz, 1H), 7.55-7.48 (m, 3H),7.47-7.41 (m, 1H), 7.27-7.22 (m, 1H), 7.17 (t, J=7.6, 1H), 5.25 (s, 2H),4.80-4.70 (m, 1H), 4.11 (dd, J=11.7, 4.6 Hz, 2H), 3.59 (td, J=12.0, 1.9Hz, 2H), 2.55-2.42 (m, 2H), 1.67-1.62 (m, 2H). LRMS (APCI+) m/z 418.0[M+H]⁺

11:1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,6-trifluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to intermediate 5A from 1E and5-chloro-2-(chloromethyl)-1-(oxan-4-yl)-1H-1,3-benzodiazole. ¹H NMR (400MHz, CDCl₃): δ 7.79-7.78 (m, 1H), 7.55-7.48 (m, 2H), 7.37-7.33 (m, 1H),7.27-7.24 (m, 1H), 6.87-6.80 (m, 1H), 5.22 (s, 2H), 4.78-4.68 (m, 1H),4.12 (dd, J=11.9, 4.6 Hz, 2H), 3.59 (td, J=12.0, 1.9 Hz, 2H), 2.57-2.43(m, 2H), 1.67-1.59 (m, 2H). LRMS (APCI+) m/z 435.8 [M+H]⁺

12:1-[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl-3,3,7-trifluoro-2,3-dihydro-1H-indol-2-one

Prepared by an analogous procedure to intermediate 5A from 1F and5-chloro-2-(chloromethyl)-1-(oxan-4-yl)-1H-1,3-benzodiazole. ¹H NMR (400MHz, CDCl₃): δ 7.68 (d, J=2.0 Hz, 1H), 7.50 (d, J=8.7 Hz, 1H), 7.43-7.39(m, 1H), 7.23-7.13 (m, 3H), 5.31 (s, 2H), 4.65-4.56 (m, 1H), 4.19 (dd,J=11.9, 4.6 Hz, 2H), 3.60 (td, J=12.0, 1.9 Hz, 2H), 2.62-2.49 (m, 2H),1.88-1.81 (m, 2H). LRMS (APCI+) m/z 435.8 [M+H]⁺

13:1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one

A solution of intermediate 5B (107 mg, 0.215 mmol) in TFA (1 mL) andCH₂Cl₂ (1 mL) was stirred at rt for 7 h. The volatiles were removedunder reduced pressure and the residue partitioned between saturatedaqueous NaHCO₃ solution (10 mL) and CH₂Cl₂ (10 mL) and separated. Theaqueous layer was extracted with CH₂Cl₂ (2×10 mL), then CH₂Cl₂:iPrOH(˜3:1, 3×20 mL), the combined organic extracts washed with brine (10mL), dried (Na₂SO₄) and the solvent removed under reduced pressure.Purification by flash chromatography (0-15% MeOH in CH₂Cl₂ with 1%NH₄OH) afforded a white solid (71 mg, 83%). ¹H NMR (400 MHz, DMSO-d₆) δ7.77-7.72 (m, 1H), 7.61-7.51 (m, 2H), 7.45 (d, J=8.3 Hz, 1H), 7.34-7.19(m, 3H), 5.28 (s, 2H), 4.30-4.22 (m, 2H), 3.78 (s, 2H), 1.72-1.61 (m,1H), 1.59-1.50 (m, 2H), 0.95 (d, J=6.6 Hz, 6H). LRMS (APCI+) m/z 398.9[M+H]⁺

The following compounds were prepared by the general BOC deprotectionprocedure described for Example 13.

TABLE 4 Compounds prepared via BOC deprotection

¹H NMR δ Example Name R (400 MHz, DMSO-d₆) LRMS AP-CI+ 141-{[5-(Aminomethyl)-1-(3- 4-F 7.70-7.62 (m, 1H), 7.55-7.53 (m, 416.9[M + H]⁺ methylbutyl)-1H-1,3- 1H), 7.46 (d, J = 8.3 Hz, 1H),benzodiazol-2-yl]methyl}- 7.23 (dd, J = 8.3, 1.6 Hz, 1H),3,3,4-trifluoro-2,3-dihydro- 7.20-7.16 (m, 1H), 7.12 (t, J =1H-indol-2-one 8.9 Hz, 1H), 5.29 (s, 2H), 4.35- 4.22 (m, 2H), 3.79 (s,2H), 1.73- 1.51 (m, 3H), 0.98-0.93 (m, 6H). 15 1-{[5-(Aminomethyl)-1-(3-4-Cl 7.60 (t, J = 8.1 Hz, 1H), 7.54- 433.0 [M + H]⁺ methylbutyl)-1H-1,3-7.52 (m, 1H), 7.46 (d, J = 8.2 Hz, benzodiazol-2-yl]methyl}-4- 1H),7.32-7.26 (m, 2H), 7.23 (dd, chloro-3,3-difluoro-2,3- J = 8.3, 1.6 Hz,1H), 5.29 (s, dihydro-1H-indol-2-one 2H), 4.29-4.23 (m, 2H), 3.80 (s,2H), 1.74-1.52 (m, 3H), 0.98- 0.93 (m, 6H). 16 1-{[5-(Aminomethyl)-1-(3-5-F 7.84-7.79 (m, 1H), 7.54-7.52 (m, 417.1 [M + H]⁺ methylbutyl)-1H-1,3-3H), 7.37-7.32 (m, 1H), 7.22 (dd, benzodiazol-2-yl]methyl}- J = 8.4, 1.6Hz, 1H), 5.28 (s, 3,3,5-trifluoro-2,3-dihydro- 2H), 4.29-4.22 (m, 2H),3.78 (s, 1H-indol-2-one 2H), 1.73-1.62 (m, 1H), 1.58- 1.50 (m, 2H),0.98-0.92 (m, 6H)

Example 17: Efficacy In Vitro

Compounds were subjected to RSV fusion assays and plaque reductionassays according to the following protocols.

RSV Fusion Assay

HEK293T ((ECACC 12022001) cells were cultured in T75 culture flasks inDulbecco's medium (DMEM) containing 10% Foetal Bovine serum (FBS), 50units per mL Penicillin and 50 μg/mL Streptomycin and warmed to 37° C.prior to use. The cells were passaged by first washing briefly with 5 mLPhosphate buffered saline (PBS), followed by addition of 2 mL of TrypsinEthylenediaminetetraacetic acid (EDTA) to detach the cells. Once cellshad detached from the flask, 8 mL media was then added to and the cellsdispersed via pipetting against the bottom of the flask.

The cells were counted and diluted to 3×10⁵ cells/mL in fresh media. TwoT75 flasks were each seeded with 15.6 mL diluted cells, cells were alsosubcultured at a ratio of between 1:2 and 1:10, to continue the stock.The flasks were then incubated for 24 h at 37° C. and 5% CO₂.

The plasmid DNA (for pFR-Luc and pcDNA3.1_Gal4/NFKB) to be transfectedinto the HEK 293T cells was first prepared in serum free media(Opti-MEM, Invitrogen), containing the transfection reagent FuGENE® 6(Promega). Serum free media was placed in a 1.5 mL eppendorf tube thenthe FuGENE 6 was added into the media. The tube was vortexed for 1 sbefore being incubated at RT for 5 min. 7.79 ng of both pFR_luc andpCDNA3.1_A2_F plasmid DNA were added to tube 1 and 7.79 ng ofpCDNA3.1_GAL4-NF-κB plasmid to tube 2. The tubes were vortexed for 1second and then incubated at room temperature for 15 min. Eachtransfection mixture was then added into the media of one of the T75flasks of 293T cells. Cells were cultured for 24 h at 37° C., 5% CO₂ ina humidified incubator.

Compounds were diluted (in a polypropylene round-bottomed 96 well plate)1:3 in a twelve point dilution curve to give top [final] of either 25μM, 3 M, 1 μM or 500 nM. A control compound was included in every assayat a top concentration of 3 M. Transfected cells were counted anddiluted to 4×10⁵ cells/mL in fresh media. 50 μL of transfectionpopulation 1 were added to all wells of the 96 well flat bottom whiteopaque assay plates. 100 μL diluted compound (2 rows per compound),control compound (one row) and controls (DMSO (0% inhibition, fourwells), 3 μM positive control (100% inhibition, four wells) and media(transfection population 1 only, four wells) were added to theappropriate wells. 50 μL of the diluted (4×105 cells/mL) population 2cells when then added to all wells, except the four wells oftransfection population 1 only where an extra 50 μL of this cellspopulation was added.

The plates were then incubated for 24 h at 37° C. and 5% CO₂. After thistime, 100 μL was removed from all wells and 60 μL of ONE-Glo™ (Promega)reagent, pre-equilibrated to room temperature, was added. Plates werethen incubated for 3 min at room temperature before luminescence wasread, using the ONE-Glo protocol, on the GloMax Explorer System(Promega) multimode reader. Analysis was carried out in Dotmaticssoftware. All raw data were background subtracted (subtraction of mean 3μM positive control value), before IC₅₀ calculation.

Plaque Reduction Assay:

The plaque reduction assay was typically performed as follows. HEp-2cells (ATCC, CCL23) were passaged in flasks and seeded in 96-well platesin DMEM containing antibiotics and supplemented with 10% FBS. Duringinoculation and subsequent incubation, cells were cultured in DMEMcontaining 3% FBS. 100 plaque forming unit (PFU)/well of RSV (RSV A2VR-1540) was mixed with ten serial dilutions of compound. Subsequently,100 μL of the virus/compound mixtures was added to confluent HEp-2 cellmonolayers. The cells and virus/compound mixtures were incubated at 35°C. in a humidified 5% CO₂ incubator for 1 day.

Cells were washed twice with PBS before adding 50% v % v EtOH/MeOH, andthen stored at −20° C. On the day of the staining, fixative was firstremoved from the plates. Plates were washed 3′ with PBS. A pre-titratedamount of the primary antibody was added in 60 μL PBS/2% milk powder,and plates incubated for 1 h at rt. The plates were washed 3× withPBS/0.05% Tween20 before addition of goat anti-mouse horse radishperoxidase in 60 μL PBS/2% milk powder, and incubated for 1 h at rt.Following three wash steps with PBS/0.05% Tween20, 60 μL ready-to-useTrueBlue was added and plates were incubated at it for 10-15 min beforeadding MilliQ water. Plates were washed once with water, incubated for30-60 min and after removal of water, air-dried in the dark.

Plates were scanned and analyzed using the Immunospot S6 UV analyzer,which is equipped with BioSpot analysis software for countingimmunostained plaques (virospots). Plaque counts were used to calculate% infection relative to the mean of the spot count (SC) in the viruscontrol wells for RSV. IC₅₀/IC₉₀ values were calculated as 50% or 90%reduction in signal, respectively, by interpolation of inhibition curvesfitted with a 4-parameter nonlinear regression with a variable slope inGraphPad 5.0 (Prism). Alternatively, where noted the plaque reductionassay was performed as follows. Hep G2 cells (ECACC, 85011430) werepassaged in flasks and seeded in 12-well plates in DMEM containingantibiotics and supplemented with 10% FBS, 24 h prior to inoculation.During inoculation and subsequent incubation, cells were cultured inDMEM containing 2% FBS. 75 plaque forming unit (PFU)/well of RSV (RSVA2, 0709161v) was mixed with 8 serial dilutions of compound.Subsequently, 200 μL of the virus/compound mixtures was added toconfluent Hep G2 cell monolayers, for a 2 h infection, with manualshaking every 15 min. Infectious supernatant was then removed andreplaced with 2 mL of overlay, comprising 4 parts of DMEM+2% FBS and 1part 4% CMC, with 0.25% DMSO. The cells were incubated at 37° C. in ahumidified 5% CO₂ incubator for 5 days.

Overlay was removed, and cells were washed with PBS before fixing with amixture of 75% acetone 25% methanol for 3 minutes and replacing withfresh PBS. If staining did not start immediately plates were stored inPBS with 0.05% Tween20 (PBS-T) at 4° C. Staining was carried out whilstshaking at 37° C. First the plates were blocked with 500 uL PBS-T/2%milk powder per well, for 1 hr. This was then replaced with 250 uLPBS-T/2% milk powder containing a pre-titrated amount of the primaryantibody (ab1128), for 90 min. The plates were washed 3×5 min withPBS-T, before addition of rabbit anti-goat horse radish peroxidase(AP106P) in 250 μL PBS-T/2% milk powder, and incubated for 1 hr.Following three wash steps with PBS-T, 250 μL of TrueBlue was added andplates were incubated at 10 min, before washing with tap water. Plateswere then air-dried and stored in the dark.

Plates were scanned and analysed using the Immunospot S6 Macro analyzer,which is equipped with BioSpot analysis software for countingimmunostained plaques. Plaque counts were input into dotmatics, wherethey were used to calculate % infection relative to the mean of the spotcount in DMSO control wells. IC₅₀ values were calculated from the curvefit, as 50% reduction in signal, with minimum value of 0% and maximum100%.

TABLE 5 Results RSV Fusion Assay RSV Plaque Reduction (n ≥ 2) AssayStrain A2 Compound IC₅₀ (nM)* IC₅₀ (nM) IC₉₀ (nM) 2 16 5.0 ^(†) 35 5 3.91.4 ^(†) 4.4 8 1.7 3.5 ^(‡) N.D. 9 2.2 12.6 ^(‡)  N.D. 10 17 6.4 ^(†) 5313 2.6 4.1 ^(‡) N.D. *The given IC₅₀ represents the mean average of atleast 2 independent experiments. ^(†) The given value is the IC₅₀obtained in the plaque reduction assay performed as described and n = 1.^(‡) The given IC₅₀ represents the mean average of at least 2independent experiments obtained in the plaque reduction assay.Performed via the alternative conditions described above. ^(§) N.D. =not determined

Example 18: In Vitro Pharmacokinetics

Compounds were subjected to the following assays to investigate livermicrosomal stability and permeability.

Microsomal incubation: Experimental Procedure

Pooled liver microsomes are purchased from a reputable commercialsupplier and stored at −80° C. prior to use. Microsomes (final proteinconcentration 0.5 mg/mL), 0.1 M phosphate buffer pH 7.4 and testcompound (final substrate concentration 3 μM, final DMSO concentration0.25%) are pre-incubated at 37° C. prior to the addition of NADPH (finalconcentration 1 mM) to initiate the reaction. The final incubationvolume is 50 uL. A control incubation is included for each compoundtested where 0.1 M phosphate buffer pH 7.4 is added instead of NADPH(minus NADPH). Two control compounds are included with each species. Allincubations are performed singularly for each test compound.

Each compound is incubated for 0, 5, 15, 30 and 45 min. The control(minus NADPH) is incubated for 45 min only. The reactions are stopped bytransferring 20 μL of incubate to 60 μL MeOH at the appropriate timepoints. The termination plates are centrifuged at 2,500 rpm for 20 minat 4° C. to precipitate the protein.

Following protein precipitation, the sample supernatants are combined incassettes of up to 4 compounds, internal standard is added and samplesanalysed by LC-MS/MS. From a plot of In peak area ratio (compound peakarea/internal standard peak area) against time, the gradient of the lineis determined. Subsequently, half-life and intrinsic clearance arecalculated.

MDR1-MDCK Permeability: Experimental Procedure

MDR1-MDCK cells obtained from the NIH (Rockville, Md., USA) are usedbetween passage numbers 6-30. Cells are seeded onto MilliporeMultiscreen Transwell plates at 3.4×10⁵ cells/cm². The cells arecultured in DMEM and media is changed on day 3. On day 4 thepermeability study is performed. Cell culture and assay incubations arecarried out at 37° C. in an atmosphere of 5% CO₂ with a relativehumidity of 95%. On the day of the assay, the monolayers are prepared byrinsing both basolateral and apical surfaces twice with Hanks BalancedSalt Solution (HBSS) at the desired pH warmed to 37° C. Cells are thenincubated with HBSS at the desired pH in both apical and basolateralcompartments for 40 min to stabilise physiological parameters.

The dosing solutions are prepared by diluting test compound with assaybuffer to give a final test compound concentration of 10 μM (final DMSOconcentration of 1% v/v). The fluorescent integrity marker luciferyellow is also included in the dosing solution. Analytical standards areprepared from test compound DMSO dilutions and transferred to buffer,maintaining a 1% v DMSO concentration.

For assessment of A-B permeability, HBSS is removed from the apicalcompartment and replaced with test compound dosing solution. The apicalcompartment insert is then placed into a companion plate containingfresh buffer (containing 1% v/v DMSO). For assessment of B-Apermeability, FIBSS is removed from the companion plate and replacedwith test compound dosing solution. Fresh buffer (containing 1% v/vDMSO) is added to the apical compartment insert, which is then placedinto the companion plate. At 60 min the apical compartment inserts andthe companion plates are separated and apical and basolateral samplesdiluted for analysis. Test compound permeability is assessed induplicate. Compounds of known permeability characteristics are run ascontrols on each assay plate.

Test and control compounds are quantified by LC-MS/MS cassette analysisusing an 8-point calibration with appropriate dilution of the samples.The starting concentration (C₀) is determined from the dosing solutionand the experimental recovery calculated from C₀ and both apical andbasolateral compartment concentrations. The integrity of the monolayerthroughout the experiment is checked by monitoring lucifer yellowpermeation using fluorimetric analysis. Lucifer yellow permeation ishigh if monolayers have been damaged.

TABLE 6 Results Pharmacokinetic property Value Liver MicrosomalStability Compound 13: 16.9/9250/366 [t_(1/2) (min); rat/dog/human]Compound 9: 22.6/118/89.8 Compound 5: 21.3/63.3/3280 Compound 10:18.2/12.4 /67.5 Permeability MDR1-MDCK Compound 13: 0.84/57.1 P_(app)(10⁻⁶ cms⁻¹) A-B/B-A Compound 9: 10.4/18.3 Compound 5: 0.21/14.5Compound 10: 19.8/34.4

Example 19: Aqueous Formulation

The compound of Example 1 is formulated as a solution in 30% w/vcaptisol (i.e. sulfobutylether-beta-cyclodextrin) at pH4 according tothe following procedure.

A carrier of 30% w/v captisol (i.e. sulfobutylether-beta-cyclodextrin)is prepared by weighing the required amount of captisol into a suitablevessel, adding approximately 80% of the final volume of water andmagnetically stirring until a solution is formed. The carrier is thenmade up to volume with water.

An aqueous solution of a compound of Example 1 is prepared by weighing175 mg of the compound into a suitable vessel and adding approximately80% of the required volume of the carrier. Using an aqueous solution ofhydrochloric acid, the pH is adjusted to pH2 and the resulting mixtureis magnetically stirred until a solution is formed. The formulation isthen made up to volume with carrier and the pH is adjusted to pH4 usingan aqueous solution of sodium hydroxide.

Example 20 Tablet Composition

Tablets, each weighing 0.15 g and containing 25 mg of a compound of theinvention are manufactured as follows:

Composition for 10,000 Tablets

Compound of the invention (250 g)

Lactose (800 g)

Corn starch (415 g)

Talc powder (30 g)

Magnesium stearate (5 g)

The compound of the invention, lactose and half of the corn starch aremixed. The mixture is then forced through a sieve 0.5 mm mesh size. Cornstarch (10 g) is suspended in warm water (90 mL). The resulting paste isused to granulate the powder. The granulate is dried and broken up intosmall fragments on a sieve of 1.4 mm mesh size. The remaining quantityof starch, talc and magnesium is added, carefully mixed and processedinto tablets.

Example 21: Injectable Formulation

Compound of the invention 200 mg Hydrochloric Acid Solution 0.1M or 4.0to 7.0 Sodium Hydroxide Solution 0.1M q.s. to pH Sterile water q.s. to10 mL

The compound of the invention is dissolved in most of the water (35°C.−40° C.) and the pH adjusted to between 4.0 and 7.0 with thehydrochloric acid or the sodium hydroxide as appropriate. The batch isthen made up to volume with water and filtered through a sterilemicropore filter into a sterile 10 mL amber glass vial (type 1) andsealed with sterile closures and overseals.

Example 22 Intramuscular Injection

Compound of the invention 200 mg Benzyl Alcohol 0.10 g Glycofurol 751.45 g Water for injection q.s to 3.00 mL

The compound of the invention is dissolved in the glycofurol. The benzylalcohol is then added and dissolved, and water added to 3 mL. Themixture is then filtered through a sterile micropore filter and sealedin sterile 3 mL glass vials (type 1).

Example 23 Syrup Formulation

Compound of invention 250 mg Sorbitol Solution 1.50 g Glycerol 2.00 gSodium benzoate 0.005 g Flavour 0.0125 mL Purified Water q.s. to 5.00 mL

The compound of the invention is dissolved in a mixture of the glyceroland most of the purified water. An aqueous solution of the sodiumbenzoate is then added to the solution, followed by addition of thesorbital solution and finally the flavour. The volume is made up withpurified water and mixed well.

1. A compound which is a benzimidazole of formula (I):

wherein: R¹ is —(CH₂)_(m)—R⁷,

R² is H, halo, —(CH₂)_(m)—NH₂, —(CH₂)_(n)—C(═NH)—NH₂ or—(CH₂)_(n)—NH—(CH₂)_(m)—NHR⁹; R³ is H, F or Cl; each of R⁴, R⁵ and R⁶ isindependently H or F; R⁷ is C₁-C₆ alkyl, CF₃, —SO₂R¹¹,—NH—(CH₂)₂—(NH)_(r)—R¹¹, —NH—CH(R⁸R⁹) or a group of the followingformula (A):

W is —(CH₂)_(m)—, —CH₂—O—CH₂—, —CH₂—S—CH₂—, —(CH₂)_(r)—S(O)₂—CH₂— or(CH₂)_(r)—NR⁸—CH₂—; m is an integer of 1 to 3; n is 1 or 2; p is 1 and Vis CH; or p is 0 and V is N; q is 0 or 1; r is 0 or 1; R⁸ is H, —SO₂R¹¹,—SO₂CF₃, —COR¹¹, —C(O)OR¹¹, —CON(R⁹)₂ or —(CH₂)_(n)SO₂R¹¹; R⁹ is H orC₁-C₆ alkyl, each R⁹ being the same or different when two are present;R¹⁰ is —SO₂R¹¹, —SO₂CF₃, —COR¹¹, —CON(R⁹)₂ or —(CH₂)_(n)SO₂R¹¹; and R¹¹is C₁-C₆ alkyl; or a pharmaceutically acceptable salt thereof.
 2. Acompound according to claim 1 wherein R¹ is —(CH₂)_(m)—R⁷ in which m is2 or 3 and R⁷ is selected from: (i) —NH—(CH₂)₂—(NH)_(r)—R⁸ wherein r is0 or 1 and R⁸ is selected from —SO₂Me, —SO₂Et and —SO₂CF₃; (ii) C₁-C₆alkyl, CF₃ or —SO₂R¹¹; (iii) —NH—CH(R⁸R⁹) wherein R⁸ is —CONH₂ or—CONMe₂ and R⁹ is C₁-C₆ alkyl; (iv) a group of formula (A) in which p is1, q is 0, V is CH and W is —(CH₂)_(r)—S(O)₂—CH₂— or —(CH₂)_(r)—NR⁸—CH₂—in which r is 0 and R⁸ is —SO₂Me or —SO₂Et; (v) a group of formula (A)in which p is 0, V is N, W is —(CH₂)_(m)— in which m is an integer of 1to 3, q is 1 and R¹⁰ is —SO₂Me, —SO₂Et, —CONH₂ or —CONMe₂; and (vi) agroup of formula (A) in which p is 0, V is N, q is 0 and W is —CH₂—CH₂—,—CH₂—S—CH₂—, —(CH₂)_(r)—S(O)₂—CH₂— or —(CH₂)_(r)—NR⁸—CH₂— in which r is0 or 1 and R⁸ is —SO₂Me, —SO₂Et or —COMe.
 3. A compound according toclaim 1 wherein: R¹ is

or in which R⁸ is H, —SO₂R¹¹, —COMe, —C(O)OR¹¹, —CON(R⁹)₂ or—(CH₂)_(n)SO₂R¹¹.
 4. A compound according to claim 3 wherein: —SO₂R¹¹ is—SO₂Me or —SO₂Et; —CON(R⁹)₂ is —CONH₂ or —CONMe₂; and —(CH₂)_(n)SO₂R¹¹is —CH₂CH₂SO₂Me.
 5. A compound according to claim 1 wherein R² is Cl or—CH₂NH₂.
 6. A compound according to claim 1 wherein the group of formula(A) is selected from the following structures:


7. A compound according to claim 1 which is selected from:1-{[5-Chloro-1-(4,4,4-trifluorobutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-({5-Chloro-1-[3-(4-methanesulfonylpiperazin-1-yl)propyl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-[(5-Chloro-1-{3-[(2-methanesulfonylethyl)amino]propyl}-1H-1,3-benzodiazol-2-yl)methyl]-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-({5-Chloro-1-[3-(3-methanesulfonylpyrrolidin-1-yl)propyl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-{[5-Chloro-1-(3-methanesulfonylpropyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;tert-Butyl4-{5-chloro-2-[(3,3-difluoro-2-oxo-2,3-dihydro-1H-indol-1-yl)methyl]-1H-1,3-benzodiazol-1-yl}piperidine-1-carboxylate;1-{[5-Chloro-1-(piperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-{[5-Chloro-1-(1-methanesulfonylpiperidin-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-({5-Chloro-1-[1-(ethanesulfonyl)piperidin-4-yl]-1H-1,3-benzodiazol-2-yl}methyl)-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,6-trifluoro-2,3-dihydro-1H-indol-2-one;1-{[5-Chloro-1-(oxan-4-yl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,7-trifluoro-2,3-dihydro-1H-indol-2-one;1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3-difluoro-2,3-dihydro-1H-indol-2-one;1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,4-trifluoro-2,3-dihydro-1H-indol-2-one;1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-4-chloro-3,3-difluoro-2,3-dihydro-1H-indol-2-one;and1-{[5-(Aminomethyl)-1-(3-methylbutyl)-1H-1,3-benzodiazol-2-yl]methyl}-3,3,5-trifluoro-2,3-dihydro-1H-indol-2-one;and the pharmaceutically acceptable salts thereof.
 8. A pharmaceuticalcomposition which comprises a compound as defined in claim 1 and apharmaceutically acceptable carrier or diluent. 9.-11. (canceled)
 12. Amethod of treating a subject suffering from or susceptible to an RSVinfection, which method comprises administering to said subject aneffective amount of a compound as defined in claim
 1. 13. (canceled) 14.(canceled)
 15. A pharmaceutical composition which comprises (a) acompound as defined in claim 1, and (b) one or more further therapeuticagents, together with a pharmaceutically acceptable carrier or diluent,wherein the one or more further therapeutic agents is selected from thegroup consisting of: (i) a RSV nucleocapsid(N)-protein inhibitor; (ii) aprotein inhibitor, such as one that inhibits the phosphoprotein (P)protein and/or large (L) protein; (iii) an anti-RSV monoclonal antibody,such as an F-protein antibody; (iv) an immunomodulating toll-likereceptor compound; (v) a respiratory virus anti-viral, such as ananti-influenza and/or anti-rhinovirus compound; and (vi) ananti-inflammatory compound.
 16. A process for producing apharmaceutically acceptable salt as defined in claim 1, which processcomprises treating a benzimidazole of formula (I) as defined in claim 1with a suitable acid in a suitable solvent.
 17. A process according toclaim 16, wherein the acid is selected from hydrochloric acid,hydrobromic acid, hydroiodic acid, sulphuric acid, nitric acid,phosphoric acid, methanesulfonic acid, benzenesulphonic acid, formicacid, acetic acid, trifluoroacetic acid, propionic acid, oxalic acid,malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid,malic acid, tartaric acid, citric acid, ethanesulfonic acid, asparticacid and glutamic acid.
 18. A method according to claim 12, which methodfurther comprises administering to the subject a further therapeuticagent selected from the group consisting of: (i) a RSVnucleocapsid(N)-protein inhibitor; (ii) another protein inhibitor, suchas one that inhibits the phosphoprotein (P) protein and/or large (L)protein; (iii) an anti-RSV monoclonal antibody, such as an F-proteinantibody; (iv) an immunomodulating toll-like receptor compound; (v)another respiratory virus anti-viral, such as an anti-influenza and/oranti-rhinovirus compound; and (vi) an anti-inflammatory compound.